Decelerating mechanism



Mal -ch 31, 1959 RJDKDODGE DECELERATING MECHANISM 2 Sheets-Sheet 1 FiledDec. 29, 1954 A INVENTOR. RONALD 0. mouse $0011,

ATTORNEY March 31, 1 959 R. b. DODGE D 9, I DECELERATING MECHANISM FiledDec. 29, 1954 2 Sheets-Sheet 2 INVENTOR. RONALD D. DODGE ATTORNEY UnitedStates 1 Patent 'ice DECELERATIN G MECHANISM Ronald D. Dodge,Poughkeepsie, N.Y., assignor to International Business MachinesCorporation, New York, N.Y., a corporation of New York ApplicationDecember 29, 1954, Serial No. 479,444

Claims. (Cl. 197183) This invention relates to movable carriage businessmachines and more particularly to an improved decelerating mechanism forabsorbing shock while stopping a machine carriage after a free or powerdriven run.

It is well recognized in the business machine art, particularlytypewriters, that some sort of shock reduction means must be employed toreduce the noise and shock of a carriage when it is returned or set freeduring a tabulation run. The art is replete with examples of snubbers,

and air cushions which operate to reduce shock and noise during thesecarriage functions, but there is still need in the art for an improvedspeed sensitive decelerating mechanism.

It is, therefore, a first object of this invention to provide such animproved decelerating mechanism for a business machine carriage.

It is a still further object of this invention to provide a carriagedecelerator which will function to slow down the carriage in agreementwith any predetermined deceleration curve.

It is a still further object of this invention to provide an improveddecelerator having operating parts that will require very littleattention or adjustment during use.

Other objects of the invention will be pointed out in the followingdescription and claims, and. illustrated in the accompanying drawings,which disclose, by way of example, the principle of the invention andthe best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a perspective view of the rear of the well known IBMtypewriter showing the decelerating mechanism operable in conjunctionwith a tabulation and. carriage return operation, respectively.

Fig. 2 is an exploded view of the elements of the tabulationdecelerator.

Fig. 3 is an exploded view of the elements of the carriage returndecelerator.

Briefly, this invention relates to a decelerator for a typewriter orbusiness machine carriage wherein a decelerating cam is selectivelyinterconnected with a power driving means that will act to limit therate of rotation of the cam. The cam, which is engageable by one end ofa bell crank, is provided with a predetermined curve for limiting therate at which the bell crank can rotate about its pivot point. During atabulation or carriage return run, a linkage system is actuatedtending'to rotate the bell crank and the decelerating cam therebyestablishing a driving relationship with the power driving means. Theslope of the cam and the driving rate of the power driving means is suchthat the carriage will be decelerated according to a predeterminedcurve.

Referring to the drawings, a typewriter carriage is illustrated ashaving a margin rack 2 carrying a margin stop 4 with the margin rackbeing movable with the carriage transversely relative to rails 6, ofwhich one is shown.

In conventional typewriter installations, as more particularly shown inthe patent, No. 2,818,959 to N. D. Walton, the typewriter is providedwith a margin control 2,879,879 Patented Mar. 31, 1959 2 lever or check8 which is slidable within fixed (slots 9) relative to supporting studs10, which are se- The sliding of margin cured to the typewriter frame.check 8 is employed to rock a margin bell crank 12 which is pivotallysuported about a stud 14 carried by the typewriter frame. Morespecifically, as the margin stop 4 is driven towards the margin check 8due to the carriage being returned to its left hand position, a blockingshoulder 16 of the margin stop 4 engages a corresponding shoulder 18 ofthe margin check 8, thereby sliding the latter to the left relative tothe studs 10 to rotate the margin bell crank 12 counterclockwise aboutits its left hand end 28 will push a tab check lever 30 out from behinda shoulder 32 freeing the check lever 30 for movement to the left withinthe limits of the slots 33.

The tab check lever 30, which is connected to a crank arm 38 via a link34, is biased to the left 'by a spring 36 which is used to rock the arm38 counterclockwise about a pivot stud 40 carried by the typewriterframe. That is, arm 38 carries integrally the crank arm 42 and thespring 36 interconnects the crank arm 42 and a portion of the typewriterframe 44.

The tab check lever 30, when set in a checking position, as moreparticularly shown in U.S. Patent 1,935,436, is engageable with a columntab stop of the type well known in the art, and provided to be movablewith carriages of IBM typewriters. As the carriage moves to the right(as viewed in Fig. 1), the check lever 30 will engage a tab stop (notshown) to drive the tab check 30 from its Fig. 2 position to the righttowards the limit position shown in Fig. 1. When the carriage isactually stopped, the tab check 30 will have been recocked behind theshoulder 32 where it will remain until the next tab operation.

The actions of the rocking of the margin lever 12" about its pivot 14,and the movement of the tab check 30 first to the left as the tab key ofa typewriter is operated, and then to the right and back to the positionshown in Fig. l as the tab stop hits the tab check are employed,respectively, in conjunction with a corresponding decelerating mechanismto slow down the rate of carriage travel at the end of either atabulating run or a carriage return operation.

Decelerator The decelerator is shown in one embodiment, as beingoperable from an auxiliary shaft 46, which is continuously driven viathe belt 47 by some motor drive 49.

The decelerating mechanism comprises, in the illustrated embodiment, apair of earns 48, 50 which are attached by means of spring clutches 52,54, respectively, to the continuously rotating shaft 46. The springclutches 52, 54 are arranged to prevent clockwise rotation of the cams48, 50 (as viewed in Fig. l), at any rate faster than that of the shaft46. More specifically, assuming that the shaft 46 is standing still,then any clockwise rotation of the cam 48 relative to the shaft 46 wouldtighten the spring 52 thereby preventing rotation of the cam 48. Sincethe shaft 46 is continuously rotating, however, the

cam 48 can rotate clockwise at a speed no greater than that of therotation of the continuously rotating shaft 46.

Decele'rato'r'on carriage return In the operation of the carriage returndecelerator, a crank arm 56 is pivotally supported about a shaft 58 topositi n a;roller.:60..ca1:ried by -the;crankarm 56 in pelocatedto-theright of the stud .40 to be engageable with a shoulder 70 carried by,the margin bell crank 12. Through this linkage system, as the marginbell crank 12 is rotated counterclockwise .about its pivot 14 (caused byinteractionof margn stop 4 and margin check 8)the shoulder .70 williacton the, arm: 68 to rock thecrank 66 clockwiseabout .-the stud 40 therebylifting orr link"64' tending to rock the crank 56 counterclockwise aboutits pivot point 58 was toy drive the roller .60 into peripheral contactwith, the:cam 48.. The peripheralinter-engagementbetween the roller 60and the cam 48 provides a torque to rotate .the cam 48 clockwise aboutthe shaft 46 thereby engaging the springclutch' 52.

Cam 48ihas the form of a decelerating curve which will slow down thecarriage at a predetermined rate. Thatis,

asgthe carriage drives. the roller 60 toward the cam 48 to rotatethelatter clockwise relative to the shaft 46, the

cam .48can be rocked, from itsFig; 1 position wherein a great radius isinengagement with roller 60 to its Fig. 3.

positionwherein its minimum radius is in engagement with roller 60." Therateof rotation of the cam from its Fig. 1v

ported about a frame supported shaft 76. The spring 72,

tends to rotate cam 48 counterclockwise, and according-4 1y, so long asthe carriage is in any steady state position, the spring 72 willdisengage the spring clutch 52 permitting shaft 46 to rotate freelywithin the hub of cam 48.

With this apparatus, and since the rate at which the arm 56 can rotatecounterclockwise is controlled by the inter-engagement of roller 60andcam 48, it is apparent that the rate of carriage deceleration isdependent entirely upon the shape of the cam 48 which shape can be setin accordance with the. expectedrate of carriage speed.

Decelerator on tabulation run' During: a' tabulation run, as heretoforedescribed, the.

tab check lever 30is first moved from a rest position (Fig; 1) out to atab stop engaging position (Fig. 2) and then returned to its restposition through the actionofoutermember.:86 which is connected via alink 88 to the cranki'arm38 which, in turn (as heretofore described), isinterconnected via the link 34 to the tab check lever 30... In theoperation of this mechanism, atabulation operation of the typewriterfirst releases tab check lever 30 for-:movement to the left to theposition shown in Fig. 2,. wherein slots 33 are at their left hand limitwith respect torsupporting studs 10. This movement of the tab check1ever;t-30.,to;its left hand limit (asshown in Fig. 2), will rock thebell crank 38 counterclockwise about the supporting=- stud-40,'-therebycausinglink88 to be moved" downwardly to rock the crank arm- 82clockwise about the supporting shaft 58 until it reaches a positionsimilar to the Fig. 1 position of the crank arm 56. A spring 90interconnects extension 86 with the hub of cam 50 via frame supportedpulley 92. The spring 90 tends to rotate the cam 50 counterclockwise,and accordingly, as the roller is moved clockwise, the spring will actto rock the cam 50,.counterclockwise with respect to shaft 46 until' itreaches apositionsimilar to that of cam 48 as viewed in Fig. 1. With themechanism'in this position, then as a tab stop strikes the tab checklever 30, the latter will be moved to-th'e right from'the'Fig. 2position towards the Fig. 1 position whichaction will pull on link 34 torock the crank arm 38 clockwise about its supporting stud 40 and therebylift on the link 88 to rock the crank 82 counterclockwise about thesupporting shaft 58 whereby the roller 80 tends to drive-the cam 50clockwise about shaft 46; Si'nce-th'e-cam 50cannotrotate any faster thanshaft 46. (becauseof spring clutch 54), and since the cam 50 is provided'with a preselected decelerating curve, the tab. operation'of thecarriage will be slowed down at a rate commensurate with the slope ofthe decelerating curve formed-on the cam 50.

The carriage will be slowed down toward the end of a tab operationuntilthe tab check 30 is driven back into its Fig; 1' position, whereupon thecrank 38 and thecrank 82 will assume'a steady'state position. Sinceroller 80 no longer tendsto drive cam 50 in a clockwise direction,clutch 54 is automatically released, thus relieving load from shaft 46;

While there have beenshown "and described and pointed out thefundamental novel features of the invention as applied-to-a preferredembodiment, it will be understood that various omissions andsubstitutions and changes in the form and details of'thedeviceillustrated and in its operation may be made by those skilled in the artwithout departing'from the spirit of the invention. It is the intention,therefore, to be-limited only as indicated by the scope .of thefollowingclaims.

What is claimed is:

1. In a typewriter having a carriage movable across a printing positionunder the influence of a power imparting means, a devicefor deceleratingsaid carriage after a free run comprising a bell crank, means positivelyinterconnecting said bell crank and said carriage during the movement ofsaid carriage through a predetermined distance to provide for therocking of said bell crank in response-to the carriage. moving throughsaid predetermined distance, power driving means, a cam, one way drivemeans interconnecting said cam and said power driving means, and meansmounting said bell crankfor engagement with saidcam to interconnecttherlatter with said power driving means assaid bell crank is rockedthereby limiting therate of rotation of said bell crank and consequentlythe rate of travel of said carriage through said predetermined distance.

2. In a typewriter having a movable carriage and means driving the sameacross a printing position, a device for decelerating saidcarriage aftera free run comprising power driving means, a crank arm pivotallysupported for rocking movement toward and away from said power drivingmeans, a cam having a decelerating curve mounted for one-Way drivingengagement with said power driving means, and linkage means positivelyinterconnecting said crankarm and said carriage during the movement ofsaid carriage through a predetermined distance to provide for therocking of the latter in response to the carriage movingthroughsaidpredetermined distance, said crank arm having releasabledrivingconnections with said cam during the rocking of said crank arm,the shape of said cam curve limiting the rate of rocking of said crankarm thereby limiting the rate oftravel of said carriage through saidpredetermined distance in conformity with the decelerating curve on saidcam.

3. In a typewriter having a carriage mounted for movement across aprinting position and power driving means for moving said carriage, adevice for decelerating said carriage comprising a bell crank pivotallysupported for rocking movement, linkage means positively connecting saidbell crank and said carriage during the power driven movement of saidcarriage through a predetermined distance to provide for the rocking ofsaid bell crank as said carriage moves through said predetermineddistance, cam means engageable with said bell crank, and positive meanscontrolling the rate of rotation of said cam means to limit the rate ofrocking of said bell crank and thereby limit the rate of movement ofsaid carriage through the said predetermined distance.

4. In a typewriter having a carriage mounted for movement across aprinting position and power driving means for moving said carriage, adevice for decelerating said carriage as it travels through apredetermined distance comprising a bell crank pivotally supported forrocking movement, linkage means positively interconnecting said bellcrank and said carriage to provide for the rocking of said bell crank asthe carriage is power driven through said predetermined distance, acontinuously driven shaft, a cam having a decelerating curve mountedcoaxially of said shaft, a crank arm mounted to rotate said cam, meanspositively interconnecting said crank arm and said bell crank, andspring clutch means interconnecting said cam and said shaft whereby saidcam is normally disconnected from said shaft but is connected thereto assaid crank arm is rotated, said cam having a continuously decreasingradius thereby limiting the rate of rotation of said crank arm and therate of movement of said carriage through said predetermined distance inaccordance with the rate of rotation of said shaft and the shape of saidcam.

5. In a typewriter having a carriage mounted for movement across aprinting position and power driving means for moving said carriage, adevice for decelerating said carriage as it travels through apredetermined distance of power driven movement comprising a crankincluding means mounting the same for pivotal movement, positive meansinterconnecting said carriage and said crank to exert a torque thereonto pivot the same as said carriage is power driven through saidpredetermined distance, and positive means controlling the maximumpivotal rate of said crank while said torque is exerted thereon therebylimiting the rate of movement of said carriage through saidpredetermined distance.

6. In a typewriter having a carriage mounted for movement across aprinting position and power driving means for moving said carriage, adevice for decelerating said carriage as it travels through apredetermined distance of power driven movement comprising a crankincluding means mounting the same for pivotal movement, positive meansinterconnecting said carriage and said crank to exert a torque thereonto pivot the same as said carriage is power driven through saidpredetermined distance, and positive energy dissipating meanscontrolling the maximum pivotal rate of said crank While said torque isexerted thereon thereby limiting the rate of movement of said carriagethrough said predetermined distance.

7. In a typewriter having a carriage mounted for movement across aprinting position and power driving means for moving said carriage, adevice for decelerating said carriage as it travels through apredetermined distance of power driven movement comprising a crankincluding means mounting the same for pivotal movement, positive meansinterconnecting said carriage and said crank to exert a torque thereonto pivot the same as said carriage is power driven through saidpredetermined distance, and means positively limiting the rate ofrotation of said crank while said torque is exerted thereon therebylimiting the rate of movement of said carriage through saidpredetermined distance.

8. In a typewriter having a carriage mounted for movement across aprinting position and power driving means for moving said carriage, adevice for decelerating said carriage as it travels through apredetermined distance of power driven movement comprising a crankincluding means mounting the same for pivotal movement, positive meansinterconnecting said carriage and said crank to exert a torque thereonto pivot the same as said carriage is power driven through saidpredetermined distance, and means positively limiting said crank torotation at a decreasing rate while said torque is exerted thereonthereby decelerating said carriage through said predetermined distance.

9. In a typewriter having a carriage mounted for movement across aprinting position and power driving means for moving said carriage, adevice for decelerating said carriage as it travels a predetermineddistance of said power driven movement comprising a cam having apredetermined contour, means pivotally mounting the same on saidtypewriter, a bell crank pivotally supported on said typewriter andincluding means engageable with said cam contour to exert a torquethereon to pivot said cam about its pivot axis as said bell crank ispivoted, means positively interconnecting said carriage and said bellcrank to exert a torque thereon to pivot the same as said carriage movesthrough said predetermined distance of power driven movement, and energydissipating means positively controlling the rate of travel of said bellcrank relative to said predetermined contour thereby limiting the rateof travel of said carriage through said predetermined distance.

10. In a business machine having a carriage mounted for movement acrossa printing position and power driving means for moving said carriage, adevice for decelerating said carriage as it travels through apredetermined distance of said power driven movement comprising a camhaving a predetermined contour, means pivotally mounting the same onsaid business machine, positive means responsive to movement of saidcarriage through said predetermined distance cooperating with saidpredetermined contour to exert a torque on said cam to rotate the sameabout its pivotal axis, said positive means limiting the rate of travelof said carriage as a function of said predetermined cam contour and therate of pivotal movement of said cam, and means positively limiting therate of pivotal movement of said cam thereby limiting the rate of travelof said carriage through said predetermined distance.

Rinsche Nov. 25, 1924 Michelsen May 21, 1935

